Insert or modify a subdatasheet
From Microsoft Office Access 2003
Note If you want to specify two or more fields in the Link Child Fields or Link Master Fields box, enter the field names separated by a semicolon (;)
You can create a self-join when you insert or modify a subdatasheet. For example, suppose you want to see the employees who report to each manager as a subdatasheet of the Employees table. Open the Employees table, click Subdatasheet on the Insert menu, click the Tables tab, and click the Employees table. Then click ReportsTo in the Link Child Fields box, and click EmployeeID in the Link Master Fields box.